This proposal describes an intervention study on the topic of screening mammography. The target groups are women aged 40-74 and primary care providers from the Family Practice, OB/GYN, and Internal Medicine departments of a large HMO. The total project period is four years. The specific aims of the project are: (1) To investigate the degree to which intervening with women patients augments the rates of mammography that are observed when working with primary care providers only; (2) To compare the effects of two patient-directed intervention strategies. One intervention is standard for all women in the group; the other will be individualized to the woman's current stage of mammography adoption, and will be guided by the Transtheoretical Model of behavior change; (3) To identify which components of intervention women and primary care providers report are most important for prompting the receipt of mammography, and how the influence persists or lessens after the interventions are withdrawn. The investigation will target a full range of mammography situations, including: women who have not yet had one (move from Precontemplation and Contemplation into Action); women who have had their first mammogram, and who now need to start a regular schedule (move from Action to Maintenance); women who are currently on the NCI/ACS schedule and need to sustain a regular schedule (stay in Maintenance); and, to help women who are off-schedule and should begin having mammograms again ("recycling" back from Precontemplation and Contemplation to Action). A randomized, three-group design is employed: Provider Intervention Only, Provider + Standard Patient Intervention, and Provider + Individualized Patient Intervention. Each group will have 480 women recruited at baseline. The first hypothesis tested is that both Provider + Patient interventions will result in an increased rate of screening mammography compared to the Provider Only condition. The second hypothesis is that there will be a greater effect for The Provider + Individualized intervention condition, compared to the Provider + Standard intervention condition. It is expected that the interventions used in this project could be disseminated to, and used at relatively low cost by, other group practice settings.